This invention relates to a downrigger release mechanism.
In one fishing technique called trolling, the fishing line is pulled behind a slowly moving boat. Because the forward movement of the boat tends to cause the relatively light fishing line, lure and hook to rise in the water, a device called a downrigger is employed to maintain the hook and lure at the desired depth for the type of fish being sought. Downriggers generally consist of a weighted line to which the fishing line is coupled by a mechanism which releases a fishing line when a fish takes the baited hook.
Various types of downrigger release mechanisims have been employed. For example, in one type of device the fishing line is wrapped around a first element which is frictionally held by a second element secured to the downrigger line. The fishing line is released when sufficient force is applied to separate the elements. This type of release device is shown, for example, in U.S. Pat. Nos. 3,765,118; 4,069,611; and 4,177,599.
Another type of prior art device holds the fishing line to the downrigger line by means of a spring and retaining element. The fishing line is released when a fish exerts sufficent pull to overcome the retaining spring. Release elements of this type are shown, for example, in U.S. Pat. Nos. 2,858,637; 3,659,370; and 3,925,920.
These prior art release devices have not been entirely satisfactory because they tend to abrade or kink the fishing line. Another shortcoming of such devices is that the required release force cannot be readily adjusted for the requirements of different species of fish.
One attempt to overcome these shortcomings is disclosed in U.S. Pat. No. 4,031,652. This device employs an adjustable magnet attached to the downrigger line and a magnetic member mounted on the fishing line. By adjusting the position of the magnet, the degree of magnetic attraction between the magnet and the magnetic member can be controlled. While this device does permit some adjustment of the required release force, the magnetic member remains attached to the fishing line after release thereby creating a drag which might be sensed by some fish causing them to release the hook. Additionally, the removable release member could become lost if the line parts or if it slides off the end of line.
Another prior art release device is disclosed in U.S. Pat. No. 4,656,776 which discloses a release device having a pivoting fishing line release lever and an adjustable magnetic coupler so that the force required to release the fishing line can be adjusted. This prior art release device, while overcoming some of the shortcomings of earlier devices, is not wholly satisfactory because it tended to jam when the fish swam beneath the release device and backwardly toward the heavier weighted line.